Sunday, March 13, 2011

Tinnitus 101: A Basic Introduction

When most people think of tinnitus, they think of ringing in the ears. But actually, the sounds that make up tinnitus are broken down into the following:
1. Ringing (37.5%)
2. Buzzing (11.2%)
3. Cricket-like (8.5%)
4. Hissing (7.8%)
5. Whistling (6.6%)
6. Humming (5.3%)

In some people it is loud and in others soft. An average of 34% say it is 8 or more on a 10-point loudness scale. It is more common as people age and is more common in men than in women. In fact, almost 12% of men age 65-74 are affected.
The differential for what causes tinnitus is actually large, but most people (and many clinicians) fail to recognize that it is important to differentiate subjective tinnitus (what you the patient appreciates) versus objective tinnitus (something that can actually be heard by something else like another person or more likely sensitive otoacoustic equipment). This is because the actual diagnoses that fit into subjective versus objective tinnitus differ.

Subjective tinnitus heard only by the patient. Causes:

 Neurologic: Head injury, whiplash, multiple sclerosis, acoustic neuroma tumor, stroke, other tumors where the cerebellum meets the pons (brainstem)
Drugs such as aspirin, NSAIDs like Aleve and Motrin etc., antibiotics (aminoglycosides), loop diuretics for hypertension, chemotherapy
Infectious: Ear injections, prior Lyme disease, meningitis, syphilis, etc.
Otologic: Long-term noise exposure, presbycusis (natural aging of the ear), cerumen impaction (ear wax), Meniere's disease, etc.

By the way, digression here: I should mention here that if I diagnose tinnitus in an individual older than 75, I consider first a tumor, then stroke (both of which can usually be ruled out with an MRI at once) and then medication changes or ear infections (viral or bacterial) then most likely age-related changes of the ear itself which just happens sometimes. Sometimes, in the elderly, there can be narrowing in the vessels leading to the head, or in the head itself, which can cause a whooshing sound due to turbulent flow of the blood.

Objective tinnitus heard by more than just the patient. Causes:
Spontaneous: Spontaneous otoacoustic emissions (your ear just makes music for the world by vibration of the outer hair cells of the cochlea-- this is actually very common and most people have randomly experienced this from time-to-time)
Muscular: Palatal myoclonus (usually due to brainstem damage causing this secondarily), spasms of the stapedius or tensor tympani muscle (the tiniest muscles in the ear than normally protect the ear from noises too loud), etc.
Pulsatile (comes and goes rhythmically): Carotid stenosis (narrowing of your carotid arteries), Vessel tumors or abnormal formations of the blood vessels either locally in the ear/brain or in the vessels that lead to the ear/nearby brain, valve abnormalities in the heart (such as the aortic valve which is the last valve before blood leaves the heart.

I like this drawing below, because it shows some of the pathologies mentioned above that can cause tinnitus and their locations (compared to the brain and nose's location). The first drawing is a small one showing you the ear and some the basic anatomy so you can compare it.

Normally, tinnitus has a straight forward cause and easy to diagnose a cause through our discussion and exam, even if I order some additional test to rule out one of the more serious possible causes (since we don't want to miss these of course).
When people do have tinnitus, 22% experience it in both ears equally, 34% only in one ear, and the remainder in both ears but with one ear being louder. So you can see that only a third of people have it in only one ear. That does not mean there is a tumor in that one ear or something happening only in that ear; we just have to consider that possibility.
Questions to help us decide what's going on:
Is it constant or episodic?
Both ears or just one?
Sudden onset or gradual?
How long has it been happening?
How loud is it?
How high is the pitch?
Are there other conditions?
Anything make it more likely such as background noise, alcohol, stress, sleepiness?
Do you have a history of noise exposure, ear infections, ear surgeries, ear deafness in the past, head injuries, recent medication changes, other things that happen at the same time?
Pain in that ear(s)?
Does it affect your daily living or ability to function?

The most common things I do to delineate the cause besides a history and head/neck exam (if needed):
MRI brain +/- MRA of the vessels, echocardiogram, audiologic evaluation, ENT referral

Treatment (assuming a benign cause): That's what everyone really cares about.
Unfortunately, although there are many medications that can cause tinnitus there are not any FDA-approved medications to treat tinnitus directly although some are used indirectly such as:
Tricyclic antidepressants ( amitriptyline and nortriptyline) These have been used with some success. But these medications are generally used for only severe tinnitus, as they can cause side effects like dry mouth, blurred vision, constipation, heart problems, and confusion in the elderly.
Alprazolam (Xanax) may help take the edge off the symptoms, but side effects can include drowsiness and nausea, and they can become habit-forming, or increase fall risks in the elderly.

Other treatments:
Noise suppression to "out compete" the tinnitus, such as white noise machines (falling rain, city traffic, ocean waves).Hearing aids if it present in people with associated hearing loss. Masking aids worn in the ear which essentially are white-noise-machine-meets hearing-aid and produce a low-level white noise in the ear during the day.Tinnitus retraining which is a wearable device that plays tonal music that over time helps one not to focus on the tinnitus.

Alternative medications:
Despite numerous trials utilizing ginkgo biloba, no firm conclusion regarding efficacy is yet reached. It is relatively benign at usual treatment doses and a dose 120-160mg should be tried if desired.

Other lifestyle strategies:
Decrease alcohol (it increases inner ear blood flow and can make tinnitus worse).
Decrease stress and get a normal amount of quality sleep.
Treat any underlying depression.
Add gentle background noise to your day (fan, soft music, low volume radio static).
Stop smoking (nicotine is an irritant).
Stop listening to loud music/exposing yourself to other loud sounds, or wear ear plugs if you cannot avoid it.